Irons usually come in a set numbered 1 through 9 where the numbers refer to the club loft angle. The higher the number, the greater the loft angle. Irons 1 through 9 typically have loft angles of from 16.degree. to 47.degree. progressing from 1 through 9. A set of irons can also include a pitching wedge, gap wedge, sand wedge, and lob wedge. Wedges may have loft angles of from about 48.degree. to 66.degree..
Golf is basically a target game. A number of modifications have been proposed to the basic club design to decrease the number of strokes required to transport the ball from the teeing ground to the hole in the green. Many ideas have been proposed to increase the accuracy of irons. A plethora of patents have been issued in the golf club art over a number of years relating to changes in the design of irons to improve alignment in the address position.
For example, Swanson U.S. Pat. No. 4,211,416 proposes a golf club iron that has the top surface of the head at an angle to the bottom surface in the face plane of the club in which the toe of the club flares upwardly and outwardly at an angel to the bottom edge defined by the sole and face when viewed from the address position. The head is provided with a flange or ledge projecting rearwardly from the top edge of the head, extending substantially along the entire length from toe to heal to define a rear sighting edge. The rear sighting edge is parallel with the bottom front edge of the golf club head. The sighting edge is said to permit the golfer to align the face normal to the intended flight path of the ball when the bottom edge of the head is obscured by turf.
Swanson U.S. Pat. No. 4,345,763 discloses a thin sighting line for lofted golfing irons of the type referred to in Swanson U.S. Pat. No. 4,211,416, but is said to eliminate the rearwardly extending ledge. The Swanson'763 patent discloses a sighting edge formed along the topmost portion of a golf club head of substantially rectangular configuration. The club of the Swanson'763 patent is said to have a top edge that is thin and provides a true sight line when addressing the ball that is not obscured by the back face of the club.
The back of the head of the club disclosed in the Swanson'763 patent extends vertically from the back bottom edge of the thick sole to a ridge that is inclined from near the top of the toe to a level about flush with the top end of the hosel at the heel. The hosel is connected by a flattened wide land to the lower portion of the heel. In one embodiment, a rounded bevel or fillet merges the ridge into a thin top portion of the club head. With the rectangular configuration of the club face, the thin top edge is said to be parallel to the bottom edge of the club defined by the intersection of the face and the sole of the club.
The Swanson clubs are not perimeter weighted clubs. The club of the '763 patent has been criticized as non-traditional in shape, weight distribution, and strike ability characteristics. The Antonious U.S. Pat. No. 4,900,028 discloses a golf club head of non-standard shape having a diverging angular top ridge that extends upwardly and outwardly from the hosel toward the toe of the golf club head. A sighting section is included on the upper portion of the top ridge that is perpendicular to the intended flight path of the ball and is parallel to the longitudinal axis between the heel and toe of the club face. The upper toe portion of the club head is substantially parallel to the sole of the club head and is therefore substantially horizontal to the ground when the club head is addressed to the ball.
As is apparent from the extent of the golf club art, slight modifications in club head design can produce significant changes in the use of the clubs and in accuracy and hitting distance. New materials for golf club heads, shafts, and balls can have a tremendous impact on whether one club design is preferred above another. Despite the plethora of current club designs and changes in materials that have occurred over the years, many golfers still have difficulty perfecting their aim and using their golf clubs to their best ability.